The Zagi M91 was a Croatian submachine gun that was produced by PHTO.
The Zagi M91 was developed by the Prva Hrvatska Tvornica Oruzja, Croatia's first national small arms factory, to meet the requirements of the Croatian independence forces during the Yugoslav Wars. Some of the design work was done by Mirko Vugrek, designer of the Agram 2000 submachine gun. Owing to manufacturing limitations and the ultimately poor reliability of the weapon, the Zagi M91 remained in production for only a year before being discontinued.
The Zagi M91 was a basic straight-blowback submachine gun chambered for the 9×19mm Parabellum cartridge, feeding from a double-stacked magazine based on the MP 40. The body was made from polymer, with the grip and trigger guard fashioned after the H&K MP5. The weapon lacked a reliable safety provision and was liable to misfire when dropped.
- The Zagi M91 was possibly named after Zagi, a squirrel mascot of the XIV Summer Universiade, held in Zagreb in 1987.